Materials: Whatever you have available, and can work with. I use wood from pallets, plywood, sheet metal, fences and wires of all sorts, whatever. I have hutches, surrounded by a fence. During daytime the rabbits can raom free in the hardly fenced in garden and meadow. At nightfall thy must return to the hutches.
The bigger the better, of course
. Hutches don't need to be that big if they can get out during the day.
Location: The closer to humans the better. I have foxes and marten nearby, after initial problems when I moved here I think I figured out how to deal with those, the fence around the hutches helps a lot, and I have a wildlife camera to see what moves around my property. I , ahm, well, think that marking my territory helps a lot to keep predators wary, I do pee at a 30m perimeter around the hutches now and then
I also have a radio running when the rabbits are out, it's a human sound, and everywhere else around here is quiet.
If something gets too close, and I can't scare it off, I kill it. The fox that killed 5 of my rabbits was a severe case of mange what drove it so close, I actually might have saved some other foxes. There was another, young fox too, but when it got inside the fence with the hutches I trapped it there for some hours, I've never seen it again.
The biggest threat for kits now are actually rats.
Birds arent really a problem as long as you don't have small rabbits or really, really big birds. Also having several hide options in their runs, and always have as many rabbits as possible out helps. If you have a lot of eagles or something there, stripes of cloth, or whatever, distanced half a meter and runnuing over their run will prevent large birds of prey to get in, they know they wouldn't be able to get out again.
About weeds and grass: Don't worry. They know exactly what to eat and what not, in a limited arrea you'll know soon what to weed out, since nothing else will be left
. Just gradually start to feed them fresh forage 2 weeks before letting them on the pasture, if not used to greens they can get tummy problems when getting unlimited access to grass.